Methods and apparatus for a stent having an expandable web structure

ABSTRACT

The present invention provides a stent comprising a tubular flexible body having a wall with a web structure that is expandable from a contracted delivery configuration to deployed configuration. The web structure comprises a plurality of neighboring web patterns, where each web patterns is composed of adjoining webs, and the web patterns are interconnected. Each adjoining web comprises a central section interposed between two lateral sections to form concave or convex configurations.

REFERENCE TO RELATED APPLICATIONS

The present application is a continuation-in-part application of U.S.patent application Ser. No. 09/582,318, filed Jun. 23, 2000, which is a371 of International Application PCT/EP99/06456, filed Sep. 2, 1999,which claims priority from German application 19840645.2, filed Sep. 5,1998.

FIELD OF THE INVENTION

The present invention relates to stents. More particularly, the presentinvention relates to stents having a web structure configured to expandfrom a contracted delivery configuration to an expanded deployedconfiguration.

BACKGROUND OF THE INVENTION

Various stent designs are known in the art. These stents form vascularprostheses fabricated from biocompatible materials. Stents are typicallyused to expand and maintain patency of hollow vessels, such as bloodvessels or other body orifices. To this end, the stent is often placedinto a hollow vessel of a patient's body in a contracted deliveryconfiguration and is subsequently expanded by suitable means, such as bya balloon catheter, to a deployed configuration.

A stent often comprises a stent body that is expandable from thecontracted to the deployed configuration. A common drawback of such astent is that the stent decreases in length, or foreshortens, along itslongitudinal axis as it expands. Such shortening is undesirable because,in the deployed configuration, the stent may not span the entire areainside a vessel or orifice that requires expansion and/or support.

It therefore would be desirable to provide a stent that experiencesreduced foreshortening during deployment.

It also would be desirable to provide a stent that is flexible, even inthe contracted delivery configuration.

It would be desirable to provide a stent having radial stiffness in theexpanded deployed configuration sufficient to maintain vessel patency ina stenosed vessel.

SUMMARY OF THE INVENTION

In view of the foregoing, it is an object of the present invention toprovide a stent that experiences reduced foreshortening duringdeployment.

It is another object to provide a stent that is flexible, even in thecontracted delivery configuration.

It is also an object to provide a stent having radial stiffness in theexpanded deployed configuration sufficient to maintain vessel patency ina stenosed vessel.

These and other objects of the present invention are accomplished byproviding a stent having a tubular body whose wall has a web structureconfigured to expand from a contracted delivery configuration to anexpanded deployed configuration. The web structure comprises a pluralityof neighboring web patterns having adjoining webs. Each web has threesections: a central section arranged substantially parallel to thelongitudinal axis in the contracted delivery configuration, and twolateral sections coupled to the ends of the central section. The anglesbetween the lateral sections and the central section increase duringexpansion, thereby reducing or substantially eliminating length decreaseof the stent due to expansion, while increasing a radial stiffness ofthe stent.

Preferably, each of the three sections of each web is substantiallystraight, the lateral sections preferably define obtuse angles with thecentral section, and the three sections are arranged relative to oneanother to form a concave or convex structure. When contracted to itsdelivery configuration, the webs resemble stacked or nested bowls orplates. This configuration provides a compact delivery profile, as thewebs are packed against one another to form web patterns resembling rowsof stacked plates.

Neighboring web patterns are preferably connected to one another byconnection elements preferably formed as straight sections. In apreferred embodiment, the connection elements extend between adjacentweb patterns from the points of interconnection between neighboring webswithin a given web pattern.

The orientation of connection elements between a pair of neighboring webpatterns preferably is the same for all connection elements disposedbetween the pair. However, the orientation of connection elementsalternates between neighboring pairs of neighboring web patterns. Thus,a stent illustratively flattened and viewed as a plane provides analternating orientation of connection elements between the neighboringpairs: first upwards, then downwards, then upwards, etc.

As will be apparent to one of skill in the art, positioning,distribution density, and thickness of connection elements and adjoiningwebs may be varied to provide stents exhibiting characteristics tailoredto specific applications. Applications may include, for example, use inthe coronary or peripheral (e.g. renal) arteries. Positioning, density,and thickness may even vary along the length of an individual stent inorder to vary flexibility and radial stiffness characteristics along thelength of the stent.

Stents of the present invention preferably are flexible in the deliveryconfiguration. Such flexibility beneficially increases a clinician'sability to guide the stent to a target site within a patient's vessel.Furthermore, stents of the present invention preferably exhibit highradial stiffness in the deployed configuration. Implanted stentstherefore are capable of withstanding compressive forces applied by avessel wall and maintain vessel patency. The web structure describedhereinabove provides the desired combination of flexibility in thedelivery configuration and radial stiffness in the deployedconfiguration. The combination further may be achieved, for example, byproviding a stent having increased wall thickness in a first portion ofthe stent and decreased wall thickness with fewer connection elements inan adjacent portion or portions of the stent.

Depending on the material of fabrication, a stent of the presentinvention may be either self-expanding or expandable by other suitablemeans, for example, using a balloon catheter. Self-expanding embodimentspreferably are fabricated from a superelastic material, such as anickel-titanium alloy. Regardless of the expansion mechanism used, thebeneficial aspects of the present invention are maintained: reducedshortening upon expansion, high radial stiffness, and a high degree offlexibility.

Methods of using stents in accordance with the present invention arealso provided.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other objects and advantages of the present invention willbe apparent upon consideration of the following detailed description,taken in conjunction with the accompanying drawings, in which likereference numerals refer to like parts throughout, and in which:

FIG. 1 is a schematic isometric view illustrating the basic structure ofa stent according to the present invention;

FIG. 2 is a schematic view illustrating a web structure of a wall of thestent of FIG. 1 in a contracted delivery configuration;

FIG. 3 is a schematic view illustrating the web structure of the stentof FIG. 1 in an expanded deployed configuration;

FIG. 4 is an enlarged schematic view of the web structure in thedelivery configuration;

FIG. 5 is a schematic view of an alternative web structure of the stentof FIG. 1 having transition sections and shown in an as-manufacturedconfiguration;

FIGS. 6A and 6B are, respectively, a schematic view and detailed view ofan alternative embodiment of the web structure of FIG. 5;

FIGS. 7A-7D are, respectively, schematic and detailed views of anotheralternative embodiment of the web structure of the stent of the presentinvention, and a cross-sectional view of the stent;

FIGS. 8A and 8B are views further alternative embodiments of the stentof the present application having different interconnection patterns;

FIGS. 9A and 9B are, respectively, a schematic and detailed view of yetanother alternative embodiment of the web structure of FIG. 5; and

FIGS. 10A-10D illustrate a method of deploying a balloon expandableembodiment of a stent constructed in accordance with the presentinvention.

DETAILED DESCRIPTION OF THE INVENTION

Referring to FIG. 1, stent 1 comprises tubular flexible body 2. Tubularflexible body 2, in turn, comprises wall 3 having a web structure, asdescribed hereinbelow with respect to FIGS. 2-9. Stent 1 and its webstructure are expandable from a contracted delivery configuration to anexpanded deployed configuration. Depending on the material offabrication, stent 1 may be either self-expanding or expandable using aballoon catheter. If self-expanding, the web structure is preferablyfabricated from a superelastic material, such as a nickel-titaniumalloy. Furthermore, stent 1 preferably is fabricated from biocompatibleor biodegradable materials. It also may be radiopaque to facilitatedelivery, and it may comprise an external coating C that retardsthrombus formation or restenosis within a vessel. The coatingalternatively may deliver therapeutic agents into the patient's bloodstream.

With reference to FIGS. 2-4, a first embodiment of the web structure ofstent 1 is described. In FIGS. 2-4, wall 3 of body 2 of stent 1 is shownflattened into a plane for illustrative purposes. FIG. 2 shows webstructure 4 in a contracted delivery configuration, with line Lindicating the longitudinal axis of the stent. Web structure 4 comprisesneighboring web patterns 5 and 6 arranged in alternating, side-by-sidefashion. Thus, the web patterns seen in FIG. 2 are arranged in thesequence 5, 6, 5, 6, 5, etc.

FIG. 2 illustrates that web patterns 5 comprise adjoining webs 9(concave up in FIG. 2), while web patterns 6 comprise adjoining webs 10(convex up in FIG. 2). Each of these webs has a concave or convex shaperesulting in a stacked plate- or bowl-like appearance when the stent iscontracted to its delivery configuration. Webs 9 of web patterns 5 arerotated 180 degrees with respect to webs 10 of web patterns 6, i.e.,alternating concave and convex shapes. The structure of webs 9 and 10 isdescribed in greater detail hereinbelow with respect to FIG. 4.

Neighboring web patterns 5 and 6 are interconnected by connectionelements 7 and 8. A plurality of connection elements 7 and 8 areprovided longitudinally between each pair of web patterns 5 and 6.Multiple connection elements 7 and 8 are disposed in the circumferentialdirection between adjacent webs 5 and 6. The position, distributiondensity, and thickness of these pluralities of connection elements maybe varied to suit specific applications in accordance with the presentinvention.

Connection elements 7 and 8 exhibit opposing orientation. However, allconnection elements 7 have the same orientation that, as seen in FIG. 2,extends from the left side, bottom, to the right side, top. Likewise,all connection elements 8 have the same orientation that extends fromthe left side, top, to the right side, bottom. Connection elements 7 and8 alternate between web patterns 5 and 6, as depicted in FIG. 2.

FIG. 3 illustrates the expanded deployed configuration of stent 1, againwith reference to a portion of web structure 4. When stent 1 is in theexpanded deployed configuration, web structure 4 provides stent 1 withhigh radial stiffness. This stiffness enables stent 1 to remain in theexpanded configuration while, for example, under radial stress. Stent 1may experience application of radial stress when, for example, implantedinto a hollow vessel in the area of a stenosis.

FIG. 4 is an enlarged view of web structure 4 detailing a portion of theweb structure disposed in the contracted delivery configuration of FIG.2. FIG. 4 illustrates that each of webs 9 of web pattern 5 comprisesthree sections 9 a, 9 b and 9 c, and each of webs 10 of web pattern 6comprises three sections 10 a, 10 b and 10 c. Preferably, eachindividual section 9 a, 9 b, 9 c, 10 a, 10 b and 10 c, has a straightconfiguration.

Each web 9 has a central section 9 b connected to lateral sections 9 aand 9 c, thus forming the previously mentioned bowl- or plate-likeconfiguration. Sections 9 a and 9 b enclose obtuse angle α. Likewise,central section 9 b and lateral section 9 c enclose obtuse angle β.Sections 10 a-10 c of each web 10 of each web pattern 6 are similarlyconfigured, but are rotated 180 degrees with respect to correspondingwebs 9. Where two sections 9 a or 9 c, or 10 a or 10 c adjoin oneanother, third angle γ is formed (this angle is zero where the stent isin the fully contracted position, as shown in FIG. 4).

Preferably, central sections 9 b and 10 b are substantially aligned withthe longitudinal axis L of the tubular stent when the stent is in thecontracted delivery configuration. The angles between the sections ofeach web increase in magnitude during expansion to the deployedconfiguration, except that angle γ, which is initially zero or acute,approaches a right angle after deployment of the stent. This increaseprovides high radial stiffness with reduced shortening of the stentlength during deployment. As will of course be understood by one ofordinary skill, the number of adjoining webs that span a circumferenceof the stent preferably is selected corresponding to the vessel diameterin which the stent is intended to be implanted.

FIG. 4 illustrates that, with stent 1 disposed in the contracteddelivery configuration, webs 9 adjoin each other in an alternatingfashion and are each arranged like plates stacked into one another, asare adjoining webs 10. FIG. 4 further illustrates that the configurationof the sections of each web applies to all of the webs which jointlyform web structure 4 of wall 3 of tubular body 2 of stent 1. Webs 9 areinterconnected within each web pattern 5 via rounded connection sections12, of which one connection section 12 is representatively labeled. Webs10 of each neighboring web pattern 6 are similarly configured.

FIG. 4 also once again demonstrates the arrangement of connectionelements 7 and 8. Connection elements 7, between a web pattern 5 and aneighboring web pattern 6, are disposed obliquely relative to thelongitudinal axis L of the stent with an orientation A, which is thesame for all connection elements 7. Orientation A is illustrated by astraight line that generally extends from the left side, bottom, to theright side, top of FIG. 4. Likewise, the orientation of all connectionelements 8 is illustrated by line B that generally extends from the leftside, top, to the right side, bottom of FIG. 4. Thus, an alternating A,B, A, B, etc., orientation is obtained over the entirety of webstructure 4 for connection elements between neighboring web patterns.

Connection elements 7 and 8 are each configured as a straight sectionthat passes into a connection section 11 of web pattern 5 and into aconnection section 11′ of web pattern 6. This is illustratively shown inFIG. 4 with a connection element 7 extending between neighboringconnection sections 11 and 11′, respectively. It should be understoodthat this represents a general case for all connection elements 7 and 8.

Since each web consists of three interconnected sections that formangles α and β with respect to one another, which angles are preferablyobtuse in the delivery configuration, expansion to the deployedconfiguration of FIG. 3 increases the magnitude of angles α and β. Thisangular increase beneficially provides increased radial stiffness in theexpanded configuration. Thus, stent 1 may be flexible in the contracteddelivery configuration to facilitate delivery through tortuous anatomy,and also may exhibit sufficient radial stiffness in the expandedconfiguration to ensure vessel patency, even when deployed in an area ofstenosis. The increase in angular magnitude also reduces and may evensubstantially eliminate length decrease of the stent due to expansion,thereby decreasing a likelihood that stent 1 will not completely span atarget site within a patient's vessel post-deployment.

The stent of FIG. 4 is particularly well-suited for use as aself-expanding stent when manufactured, for example, from a shape memoryalloy such as nickel-titanium. In this case, web patterns 5 and 6preferably are formed by laser-cutting a tubular member, whereinadjacent webs 9 and 10 are formed using slit-type cuts. Only the areascircumferentially located between connection members 7 and 8 (shadedarea D in FIG. 4) require removal of areas of the tubular member. Theseareas also may be removed from the tubular member using laser cuttingtechniques.

Referring now to FIG. 5, an alternative embodiment of the web structureof stent 1 is described. FIG. 5 shows the alternative web structure inan as-manufactured configuration. The basic pattern of the embodiment ofFIG. 5 corresponds to that of the embodiment of FIGS. 2-4. Thus, thisalternative embodiment also relates to a stent having a tubular flexiblebody with a wall having a web structure configured to expand from acontracted delivery configuration to the deployed configuration.

Likewise, the web structure again comprises a plurality of neighboringweb patterns, of which two are illustratively labeled in FIG. 5 as webpatterns 5 and 6. Web patterns 5 and 6 are again provided with adjoiningwebs 9 and 10, respectively. Each of webs 9 and 10 is subdivided intothree sections, and reference is made to the discussion providedhereinabove, particularly with respect to FIG. 4. As will of course beunderstood by one of skill in the art, the stent of FIG. 5 will have asmaller diameter when contracted (or crimped) for delivery, and may havea larger diameter than illustrated in FIG. 5 when deployed (or expanded)in a vessel.

The embodiment of FIG. 5 differs from the previous embodiment by theabsence of connection elements between web patterns. In FIG. 5, webpatterns are interconnected to neighboring web patterns by transitionsections 13, as shown by integral transition section 13 disposed betweensections 9 c and 10 c. Symmetric, inverted web patterns are therebyobtained in the region of transition sections 13. To enhance stiffness,transition sections 13 preferably have a width greater than twice thewidth of webs 9 or 10.

As seen in FIG. 5, every third neighboring pair of webs 9 and 10 isjoined by an integral transition section 13. As will be clear to thoseof skill in the art, the size and spacing of transition sections 13 maybe altered in accordance with the principles of the present invention.

An advantage of the web structure of FIG. 5 is that it provides stent 1with compact construction coupled with a high degree of flexibility inthe delivery configuration and high load-bearing capabilities in thedeployed configuration. Furthermore, FIG. 5 illustrates that, as withconnection elements 7 and 8 of FIG. 4, transition sections 13 have analternating orientation and are disposed obliquely relative to thelongitudinal axis of the stent (shown by reference line L). FIG. 5 alsoillustrates that, especially in the deployed configuration, an H-likeconfiguration of transition sections 13 with adjoining web sections isobtained.

The stent of FIG. 5 is well-suited for use as a balloon-expandablestent, and may be manufactured from stainless steel alloys. Unlike thestent of FIG. 4, which is formed in the contracted deliveryconfiguration, the stent of FIG. 5 preferably is formed in a partiallydeployed configuration by removing the shaded areas D′ between webs 9and 10 using laser-cutting or chemical etching techniques. In this case,central sections 9 b and 10 b are substantially aligned with thelongitudinal axis L of the stent when the stent is crimped onto thedilatation balloon of a delivery system.

Referring now to FIGS. 6 and 7, alternative embodiments of the webstructure of FIG. 5 are described. These web structures differ from theembodiment of FIG. 5 in the spacing of the transition sections. Webstructure 15 of FIGS. 6A and 6B provides a spacing of transitionsections 16 suited for use in the coronary arteries. FIG. 6A shows theoverall arrangement, while FIG. 6B provides a detail view of region A ofFIG. 6A. Other arrangements and spacings will be apparent to those ofskill in the art and fall within the scope of the present invention.

Web structure 17 of FIGS. 7A-7D provides stent 1 with a variable wallthickness and a distribution density or spacing of transition sections16 suited for use in the renal arteries. FIG. 7A shows the arrangementof web structure 17 along the length of stent 1, and demonstrates thespacing of transition sections 18. FIGS. 7C and 7D provide detail viewsof regions A and B, respectively, of FIG. 7A, showing how the spacingand shape of the webs that make up web structure 17 change as stent 1changes along its length. In particular, as depicted (not to scale) inFIG. 7D, stent 1 has first thickness t₁ for first length L₁ and secondthickness t₂ for second length L₂.

The variation in thickness, rigidity and number of struts of the webalong the length of the stent of FIGS. 7A-7D facilitates use of thestent in the renal arteries. For example, the thicker region L₁ includesmore closely spaced and sturdier struts to provide a high degree ofsupport in the ostial region, while the thinner region L₂ includes fewerand thinner struts to provide greater flexibility to enter the renalarteries. For such intended applications, region L₁ preferably has alength of about 6-8 mm and a nominal thickness t₁ of 0.21 mm, and regionL₂ has a length of about 5 mm and a nominal thickness t₂ of about 0.15mm.

As depicted in FIGS. 7A-7D, the reduction in wall thickness may occur asa step along the exterior of the stent, such as may be obtained bygrinding or chemical etching. One of ordinary skill in the art willappreciate, however, that the variation in thickness may occur graduallyalong the length of the stent, and that the reduction in wall thicknesscould be achieved by alternatively removing material from the interiorsurface of the stent, or both the exterior and interior surfaces of thestent.

In FIGS. 8A and 8B, additional embodiments of web structures of thepresent invention, similar to FIG. 5, are described, in which line Lindicates the direction of the longitudinal axis of the stent. In FIG.5, every third neighboring pair of webs is joined by an integraltransition section 13, and no set of struts 9 a-9 c or 10 a-10 cdirectly joins two transition sections 13. In the embodiment of FIG. 8A,however, integral transition sections 20 are arranged in a pattern sothat the transition sections span either four or three adjacent webs.For example, the portion indicated as 22 in FIG. 8A includes threeconsecutively joined transition sections, spanning four webs. In thecircumferential direction, portion 22 alternates with the portionindicated at 24, which includes two consecutive transition sections,spanning three webs.

By comparison, the web pattern depicted in FIG. 8B includes onlyportions 24 that repeat around the circumference of the stent, and spanonly three webs at a time. As will be apparent to one of ordinary skill,other arrangements of integral transition regions 13 may be employed,and may be selected on an empirical basis to provide any desired degreeof flexibility and trackability in the contracted deliveryconfiguration, and suitable radial strength in the deployedconfiguration.

Referring now to FIGS. 9A and 9B, a further alternative embodiment ofthe stent of FIG. 8B is described, in which the transition sections areformed with reduced thickness. Web structure 26 comprises transitionsections 27 disposed between neighboring web patterns. Sections 27 arethinner and comprise less material than transition sections 20 of theembodiment of FIG. 8B, thereby enhancing flexibility without significantreduction in radial stiffness.

Referring now to FIGS. 10A-10D, a method of using a balloon expandableembodiment of stent 1 is provided. Stent 1 is disposed in a contracteddelivery configuration over balloon 30 of balloon catheter 32. As seenin FIG. 10A, the distal end of catheter 32 is delivered to a target siteT within a patient's vessel V using, for example, well-knownpercutaneous techniques. Stent 1 or portions of catheter 32 may beradiopaque to facilitate positioning within the vessel. Target site Tmay, for example, comprise a stenosed region of vessel V at which anangioplasty procedure has been conducted.

In FIG. 10B, balloon 30 is inflated to expand stent 1 to the deployedconfiguration in which it contacts the wall of vessel V at target siteT. Notably, the web pattern of stent 1 described hereinabove minimizes alength decrease of stent 1 during expansion, thereby ensuring that stent1 covers all of target site T. Balloon 30 is then deflated, as seen inFIG. 10C, and balloon catheter 32 is removed from vessel V, as seen inFIG. 10D.

Stent 1 is left in place within the vessel. Its web structure providesradial stiffness that maintains stent 1 in the expanded configurationand minimizes restenosis. Stent 1 may also comprise external coating Cconfigured to retard restenosis or thrombosis formation around thestent. Coating C may alternatively deliver therapeutic agents into thepatient's blood stream.

Although preferred illustrative embodiments of the present invention aredescribed hereinabove, it will be evident to one skilled in the art thatvarious changes and modifications may be made therein without departingfrom the invention. It is intended in the appended claims to cover allsuch changes and modifications that fall within the true spirit andscope of the invention.

What is claimed is:
 1. A stent comprising: a tubular body with a wallhaving a web structure configured to expand from a contracted deliveryconfiguration to an expanded deployed configuration, the web structurecomprising a plurality of interconnected, neighboring web patterns, eachweb pattern having a plurality of adjoining webs, each adjoining webcomprising a central section interposed between first and second lateralsections, wherein, in a non-deployed configuration, each of the firstand second lateral sections joins the central section at an obtuse angleless than 180°, each central section has a longitudinal axis disposed atan oblique angle relative to a longitudinal axis of the tubular body,longitudinal axes of adjacent central sections intersect, and adjacentones of the neighboring web patterns having alternating concavity. 2.The stent of claim 1, wherein each of the three sections of eachadjoining web is straight.
 3. The stent of claim 1, wherein a thicknessof the wall of the tubular body changes along a length of the tubularbody.
 4. The stent of claim 1, wherein the first angle is equal to thesecond angle.
 5. The stent of claim 1, wherein the central section andfirst and second lateral section of each adjoining web form a bowl-likeconfiguration.
 6. The stent of claim 1 further comprising a plurality ofconnection elements configured to interconnect the plurality of webpatterns.
 7. The stent of claim 6, wherein each of the plurality ofconnection elements comprises a straight section.
 8. The stent of claim6, wherein each web pattern comprises a plurality of connectionsections, the connection elements configured to couple neighboringconnection sections together to interconnect the plurality of webpatterns.
 9. The stent of claim 6, wherein the plurality of connectionelements comprise a first plurality of connection elements disposed in afirst orientation and a second plurality of connection elements disposedin a second orientation.
 10. The stent of claim 9, wherein the first andsecond plurality of connection elements, respectively, are disposedbetween neighboring web patterns in an alternating arrangement.
 11. Thestent of claim 1 further comprising a plurality of transition sectionsconfigured to interconnect neighboring web patterns.
 12. The stent ofclaim 11, wherein the transition sections comprise extensions ofneighboring adjoining webs.
 13. The stent of claim 1, wherein the webstructure is fabricated from a superelastic material.
 14. The stent ofclaim 1, wherein the stent is fabricated from a biocompatible orbiodegradable material.
 15. The stent of claim 1, wherein the tubularbody is flexible in the contracted delivery configuration.
 16. The stentof claim 1, wherein the web structure is configured to self-expand fromthe contracted delivery configuration to the expanded deployedconfiguration.
 17. The stent of claim 1, wherein the web structure isconfigured to expand by application of pressure to an interior surfaceof the stent from the contracted delivery configuration to the expandeddeployed configuration.
 18. The stent of claim 1, wherein a third angleis formed where adjoining web patterns are joined, the third angle beingacute in the contracted delivery configuration.
 19. The stent of claim18, wherein the third angle increases in magnitude when the webstructure deploys from the contracted delivery configuration to theexpanded deployed configuration.
 20. The stent of claim 18, wherein thethird angle approaches a right angle after deployment of the stent. 21.The stent of claim 1, wherein the number of adjoining webs that span acircumference of the stent is selected corresponding to a vesseldiameter in which the stent is to be implanted.
 22. The stent of claim12 wherein each transition section has a transition width having a widthgreater than twice the width of the central section.
 23. The stent ofclaim 1 further comprising a plurality of connection sections configuredto adjoin the adjoining webs.
 24. The stent of claim 1 furthercomprising an coating partially covering the tubular body.
 25. The stentof claim 24 wherein the coating is configured to retard restenosis. 26.The stent of claim 24, wherein the coating is configured to retardthrombus formation around the stent.
 27. The stent of claim 24, whereinthe coating is configured to deliver therapeutic agents to the patient'sblood stream.
 28. A method for stenting at a target site within apatient's vessel comprising: providing a stent comprising a tubular bodywith a wall having a web structure, the web structure comprising aplurality of interconnected, neighboring web patterns, each web patternhaving a plurality of adjoining webs, each adjoining web comprising acentral section interposed between two lateral sections, wherein, in anon-deployed configuration, each of the two lateral sections joins thecentral section at an obtuse angle less than 180°, each central sectionhas a longitudinal axis disposed at an oblique angle relative to alongitudinal axis of the tubular body, longitudinal axes of adjacentcentral sections intersect, and adjacent ones of the neighboring webpatterns having alternating concavity; percutaneously delivering thestent to the target site within the patient's vessel in a contracteddelivery configuration; and deploying the stent to an expanded deployedconfiguration, wherein the stent engages the target site.
 29. The methodof claim 28, wherein deploying the stent to an expanded deployedconfiguration further comprises increasing a third angle disposedbetween adjoining webs to substantially a right angle.
 30. The method ofclaim 28, wherein expanding the stent comprises increasing a magnitudeof the angles between the two lateral sections and the central section.31. The method of claim 30, wherein increasing the magnitude of theangles increases a radial stiffness of the stent.
 32. The method ofclaim 30, wherein increasing the magnitude of the angles maintains asubstantially constant length of the stent during expansion.
 33. Themethod of claim 29 wherein deploying the stent to an expanded deployedconfiguration comprises using a delivery system to apply aradially-outwardly directed force against an interior surface of thestent.
 34. A stent comprising: a tubular body with a wall having a webstructure configured to expand from a contracted delivery configurationto an expanded deployed configuration, the web structure comprising aplurality of interconnected, neighboring web patterns, each web patternhaving a plurality of adjoining webs, each adjoining web comprising acentral section interposed between first and second lateral sections,wherein the central section has a longitudinal axis disposed at anoblique angle relative to a longitudinal axis of the tubular body, andadjacent ones of the neighboring web patterns having alternatingconcavity, and a plurality of transition sections configured tointerconnect neighboring web patterns, wherein each transition sectionhas a transition width greater than twice a width of the centralsection, wherein each of the three sections of each adjoining web isstraight.
 35. The stent of claim 34, wherein the central section andfirst and second lateral section of each adjoining web form a bowl-likeconfiguration.
 36. The stent of claim 34, wherein the transitionsections comprise extensions of neighboring adjoining webs.
 37. Thestent of claim 34, wherein the web structure is fabricated from asuperelastic material.
 38. The stent of claim 34, wherein the stent isfabricated from a biocompatible or biodegradable material.
 39. The stentof claim 34, wherein the tubular body is flexible in the contracteddelivery configuration.
 40. The stent of claim 34, wherein the webstructure is configured to self-expand from the contracted deliveryconfiguration to the expanded deployed configuration.
 41. The stent ofclaim 34, wherein the web structure is configured to expand byapplication of pressure to an interior surface of the stent from thecontracted delivery configuration to the expanded deployedconfiguration.
 42. The stent of claim 34 further comprising an coatingpartially covering the tubular body.
 43. The stent of claim 42 whereinthe coating is configured to retard restenosis.
 44. The stent of claim43, wherein the coating is configured to retard thrombus formationaround the stent.
 45. The stent of claim 44, wherein the coating isconfigured to deliver therapeutic agents to the patient's blood stream.46. The stent of claim 34, wherein a thickness of the wall of thetubular body changes along a length of the tubular body.
 47. A methodfor stenting at a target site within a patient's vessel comprising:providing a stent comprising a tubular body with a wall having a webstructure, the web structure comprising a plurality of interconnected,neighboring web patterns, each web pattern having a plurality ofadjoining webs, each adjoining web comprising a central sectionsinterposed between two lateral sections, wherein the central section hasa longitudinal axis disposed at an oblique angle relative to alongitudinal axis of the tubular body, and adjacent ones of theneighboring web patterns having alternating concavity and a plurality oftransition sections configured to interconnect neighboring web patterns,wherein each transition section has a transition width greater thantwice a width of the central section, wherein each of the three sectionsof each adjoining web is straight; percutaneously delivering the stentto the target site within the patient's vessel in a contracted deliveryconfiguration; and deploying the stent to an expanded deployedconfiguration, wherein the stent engages the target site.
 48. The methodof claim 47, wherein each of the first lateral sections joins thecentral section at a first angle and each of the second lateral sectionsjoins the central section at a second angle, and expanding the stentcomprises increasing a magnitude of the first and second angles.
 49. Themethod of claim 48, wherein increasing the magnitude of the anglesincreases a radial stiffness of the stent.
 50. The method of claim 48,wherein increasing the magnitude of the angles maintains a substantiallyconstant length of the stent during expansion.
 51. The method of claim47 wherein deploying the stent to an expanded deployed configurationcomprises using a delivery system to apply a radially-outwardly directedforce against an interior surface of the stent.
 52. The method of claim47, wherein deploying the stent to an expanded deployed configurationfurther comprises increasing a third angle disposed between adjoiningwebs to substantially a right angle.